Alkylation of hydrocarbons



Patented May 3, 1949 ALKYLATION'LOF HYDKQJCARBONST Garlisle" Mamas-kw HighIand ParkpIH-I;tassignom t-lT11- Purel0ilCompany;?.Cliicago; I112; armorporation of Ohio;-

r wing-1 Application *March 15,1945; serial No. 5821990 In; accordance. withnmytzinventionnparaffinicuhydrecarbonsawhichm ay :consistioi normal-palata fins .:orisoparaffins.=.having, :ironnB to 1 c carbonv atcmsapera-moleculeizsuclr.astpnopanei'butanesisoe Reactiom-of normal and iso parafliiishaving butane, pentaneg:hexane;anda:heptanesnonz'anyc' from" 3 "to 5 carbon atomsin themole'cule' with' unsaturatedhydrocarbons: such as ethylene-a propylene, butyl'ene acetylene and'butadiene ate: temperatures-withinthe range of approximately 750 -1200 and at pressuresof' from -500 5000 o onrstabiiizer; gasxseparated. from; lowwpressureac pounds per square-'inch or more-ihave been-sugges-tedin the prior art2: Iri' one -type -ofa-1process the paraflins -arepassedth'rough an-elongate'd re-wactidncoil wherein theya-re heated to the desired reaction-temperaturemilder '-the -desired pressurw torkeep the olefin concentrationzbetweerrappmx and olefins are injected intothe--coil at 'aplu rality of =-'spaced points in-"order to =-maintain-= the olefinconcentration in the miiiture between ap proximately 2 to 10 per cent by weig htv- Processesofithis-type-are disel'osed in Unitedstates Patents 2,002,394; 2;104;296-- and 2 2701-? 00-5- Iri anothew" type of processforireaeting-paraffihswith olefins a-mixture containing in excess of'50 per cent of parafihis and -in excess-of 10 per-cent of olefins'is heated to the desired reaction temperature underreaction pressure and charged to an enlarged reaction zone of suchlstructurenas to, cause a high degree of circulationan'dturbulent'mixing there- Snchwasprocessais: discloseddn :UnitedcStates Patent 2,266,019.

I have discovered that.reaction..between paraffins and olefins under high temperature-high pressures-conditions can be :greatly accelerated:riflv the reactionxis..caizriectiontizdriiathelzpresenca cilia; promoter comprising .azsmallrnmount OfZ-Taz. ture of bromine with one or more compounds selected from the group consisting of carbon tetrachloride, carbon tetrabromide, chloroform and bromoform.

An object of the invention is to provide an improved process for reacting parafifins with olefin hydrocarbons.

Another object of the invention is to provide a promoter for accelerating the rate of reaction of parafiins with olefinic hydrocarbons under elevated temperature and pressure.

Still another object of the invention is to provide a process in which increased yields of saturated hydrocarbons of high octane value can be obtained from the reaction of olefins and parafiins at elevated temperature and pressure.

A still further object of the invention is to provide a process in which a more valuable product can be obtained by reaction of olefins and paraffins at elevated temperature and pressure.

mixture thereof; maybe heated to a;temperatur.e

ctr-approximately 750410091: in-ga. .heatingico ilafter which gas-or;- liquid :ric-lmuolefimiascfor': example ethylenecpropylene;.butylenes; amylenes:

high temperature;:thermallys'cracked gasoline, iriiectednintopthe.- .heated. stream aoirparafiiniac hydrocarbons at; a :pluralityrof 'points: in :the manic new :discl'osedoin; the. aforesaid patents=in-::;ond*

matelyat 2ilto 10::pen cent ."byiweight -ofi the mixture. Asmix'tura ofJca-r-bon: tetrachloride, :carltronastetra-e bromide chloroformagor. bromofor mrlor: any= comm s bin-ationi \there'of with '-'bromine,s isuaddedctmthe *charge: undergoing. reaction- .ina'tans amountrlrangaev ing from-i iapproxima-telyw-0s5 :to ..10; periacen-ti byl' weightzrofs theltotal' hydrocarbonschargen. The-e amountaof bromine :is preferably: between: Oflrpenr I cent lbyweight. and 5 tpeiuscentdbyiweight'pfi.theic hydrocarbons chargeg and? the carbon: tetra-1.. chlorideg or-zoth'er group. compoundgismreferablyii' between: 0.4 and 9".9 per: :rcent :by =-wei'ghta'ioi .thec hydrocarbon charge. The entire eamonntstlofir. promoter may be mixed with the liquidiparaifiiis charged-'to the heating :coil or the promoter may be -iniectedtinto the -reaction coil ata pluraliitw' ofpoin'ts.

Admixture: of bromine' with olefins; charged :toi'. tlie syst-em before.*mixturei-of the: olefin's withtthee -paraffinssshomldg bezayoidedbecauses ofirtheifaetr that bromine readily reacts with unsaturates.

When the process is carried out using a turbulent reactor such as disclosed in Patent 2,266,019 the hydrocarbons charged to the process may be the gases from a high pressure thermal or a catalytic cracking process from which the major portion of the methane and hydrogen have been removed. Ordinarily, these gases will contain considerably less than 50 per cent of olefins with the major portion consisting of C3 and C4 paraflins. In this type of operation the promoter is preferably injected directly into the reaction zone in order to prevent bromination of the olefins before the reactants are heated to reaction temperature. However, the effect of the promoter can be realized to a large extent even where the catalyst is mixed With the charging gas prior to charging it to the heating coil.

In carrying out the reaction temperatures of 750-1100 F. and pressures in excess of 500 pounds, and preferably in excess of 2,000 pounds per square inch are maintained in the reaction zone. Conversion rates equalling those obtained in purely thermal operations can be obtained using promoters in accordance with my invention at considerably lower temperatures. Under the same conditions of temperature and pressure when promoters in accordance with my invention are used, the rate of conversion is greatly ac-. celerated with the result that a higher yield of desirable high octane hydrocarbons boiling within the gasoline range is obtained. Isoparafiinic charging stocks require lower temperatures and pressures than are required for normal paraffinic charging stock to obtain the desired amount of alkylation. The time of reaction should be sufi'icient to cause the major portion of the olefins' to be converted to higher boiling hydrocarbons but insufficient to cause substantial cracking of the paraffinic charging stock to lower boiling hydrocarbons. Reaction times may vary from a few seconds to approximately minutes depending on the temperature, pressure and reactants. Higher pressures and temperatures accelerate the reaction for any given charging stock.

As an example of the process a feed stock comprising chiefly straight and branched chain hydrocarbons having 3 to 7 carbon atoms per molecule is mixed with a mixture of ethylene and propylene so that the resultant mixture contains less than 10 per cent by Weight of olefins. To this mixture is added 3 per cent by weight of carbon tetrachloride and 0.5 per cent by weight of bromine. The mixture is passed through a reaction coil wherein it is heated to 940 F. under a pressure of 2,000 pounds per square inch, and is permitted to remain in the reaction coil for a sufiicient period of time to permit substantially all the propylene to react with the paraffins and more than 60 per cent of the ethylene to react. The resulting liquid product will be a gasoline of high octane number and high blending value suitable for aviation gasoline after it has been freed of halogens by neutralization with alkali, or other suitable method. Under these same conditions of temperature and pressure the time required to obtain the same amount of conversion is considerably longer.

It is claimed:

1. The method of reacting paraffins having at least 3 carbon atoms per molecule with olefinic hydrocarbons comprising subjecting a mixture of said parafins and olefinic hydrocarbons to temperatures of approximately '750-1100 F. and pressures in excess of 500 pounds per square inch 4 in the presence of a small amount of bromine and a small amount of carbon tetrachloride.

2. The method of reacting olefinic hydrocarbons with paraffin hydrocarbons comprising subjecting a mixture of paraffin hydrocarbons comprised chiefly of hydrocarbons having from 3 to 7 carbon atoms per molecule and not more than 10% by weight of olefins containing 3 to 5 carbon atoms per molecule to temperatures of the order of 750 to 1100 F. at pressures in excess of 2,000 pounds per square inch in the presence of approximately 0.1 to 5 per cent by Weight of bromine and approximately 0.4 to 9.9 per cent by weight of a compound selected from the group consisting of carbon tetrachloride, carbon tetrabromide, chloroform and bromoform for a period of time suflicient to permit the major portion of the olefins to react to form higher boiling hydrocarbons.

3. Method in accordance with claim 2 in which the group compound is carbon tetrachloride.

4. The method of reacting parafiins having at least 3 carbon atoms per molecule with olefim'c hydrocarbons comprising, subjecting a mixture of said paraffins and olefinic compounds to temperatures of approximately 750-1100 F. and pressures in excess of 500 pounds per square inch in the presence of a catalyst consisting of about 0.1 to 5 per cent of the charge by weight of bromine and 0.4 to 9.9 per cent of the charge by weight of a compound selected from the group consisting of carbon tetrachloride, carbon tetrabromide, chloroform, and bromoform.

5. The method in accordance with claim 4 in which the catalyst consists of bromine and carbon tetrachloride.

6. The method in accordance with claim 4 in which the pressure is in excess of 2,000 pounds per square inch.

7. The method in accordance with claim 4 in which the olefinic hydrocarbon content of the mixture is below per cent by weight.

8. The method in accordance with claim 4 in which the olefinic hydrocarbon content of the mixture is below 10 per cent by weight.

CARLISLE M. THACKER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,361,356 Sachanen et a1 Oct. 24, 1944 2,410,107 Sachanen et al Oct. 29, 1946 

